What is "lorandite"

n. (context mineralogy English) A monoclinic-prismatic mineral containing arsenic, sulfur, and thallium.

Lorándite is a thallium arsenic sulfosalt with the chemical formula: TlAsS. Though rare, it is the most common thallium-bearing mineral. Lorandite occurs in low-temperature hydrothermal associations and in gold and mercury ore deposits. Associated minerals include stibnite, realgar, orpiment, cinnabar, vrbaite, greigite, marcasite, pyrite, tetrahedrite, antimonian sphalerite, arsenic and barite.

The mineral is being used for detection of solar neutrino via a certain nuclear reaction involving thallium. It has a monoclinic crystal structure consisting of spiral chains of AsS tetrahedra interconnected by thallium atoms, and can be synthesized in the laboratory.